Automatic printing machine

ABSTRACT

An automatic printing machine which comprises a continuously driven film cylinder for receiving a printing film. A rubberblanket operates synchronously with the film cylinder. An inking unit is provided for the inking of a printing image, a preadjustable print-run counter and an automatic paper feed are arranged. An etching device for the hydrophilizing of a zinc oxide film provided on the circumference of the film cylinder. A film insert device with a waiting station includes a stop means provided with feeler switches and swingable out of the path of the film. A pair of transport rollers is provided. A singlerevolution clutch for driving said transport rollers in synchronism with the film cylinder. A film feed device conveys the film originating from an electrostatic copy machine against the stop, and the film cylinder is provided with a gripping and ejector device.

Schinke et a1.

14 1 Feb. 18, 1975 1 AUTOMATIC PRINTtNG MACHINE 3,375,779 4/1968 Mallory et a]. 101/142 x 3, 12,67 19 11.... 1 I [75] Inventors: Hem Jpach'm 3.126.672 Z1922 11 1 nil/1 1 Umerklmach; Hans-Dieter Uhmg, 3,496,864 2/1970 Tonkin ct 111. 1111/14: St. Georgen, both of Germany [73] Assignee: Firma Mathias Bauerle GmbH, St. g

Georgian Germany Assistant ExuminerEdward M. Coven Attorney, Agent, or FirmErnest G. Montague; Karl [22] Flled: June 71 1973 F. Ross; Herbert Dubno [21] Appl. No: 367,746

57 ABSTRACT Related U.S. Applicatlon Data l t h h n au oma 1c prm mg mac me w 1c comprises a [63] 3 51 2 21 25 of June 1970 continuously driven film cylinder for receiving a printing film. A rubber-blanket operates synchronously with the film cylinder. An inking unit is provided for the [30] Forelgn Apphcanon Prmmy Data 7 inking of a printing image, a pre-adjustable print-run 1970 Germany 003590 counter and an automatic paper feed are arranged. An etching device for the hydrophilizing of a zinc oxide U-Su 1 I 1 I v I I I s v 1 I 1 i der- A insert device with a] Waiting Station 8] held of Search 101/1325 cludes a stop means provided withleeler switches and swingable out of the path of the film. A pair of trans [56] References C'ted port rollers is provided. A single-revolution clutch for UNITED STATES PATENTS driving said transport rollers in synchronism with the 2.756.672 7/1956 George 101/144 film cylinder. A film feed device conveys the film orig- 3.056,346 10/1962 Gammeter et alw. 101/144 inating from an electrostatic copy machine against the 3,102,471) Cfflgg'ClI all 101/144 top and the cylinder is provided with a 3,238,868 3/1966 Ritzerfeld et a1. 101/1325 X and ejector device 3,264,981 8/1966 Burger et al. 101/144 3,303,778 2/1967 Tonkin et a1. 101/144 2 Claims, 14 Drawing Figures 15C) 147 Mg' E8 RR? 7; i

NN/(VWNAVNAVN/(VNAVNAVAVA KQ7/ PATENTED FEB] 8I975 SHEET 1 OF 8 am m9 .Nvm

I QJENTEUFEB 1 8 iETS SHEET 2 BF 8 4 Alla- 1M6 I Illa PATEHTED 8 5 sum 70F 8 FIGJZ AUTOMATIC PRINTING MACHINE This is a continuation application of the copending application Ser. No. 42,936, filed June 3, l970 now abandoned.

The present invention relates to an automatic printing press having a continuously driven foil cylinder adapted to receive a printing foil and a rubber-blanket and/or impression cylinder operating synchronously therewith, an inking mechanism for inking the image on the foil cylinder, a pre-adjustable printing-run counter and an automatic paper feed.

Such automatic printing machines are very widely used today and are generally referred to as offset printing machines or directprinting machines. In so-called offset printing machines, a printing master adapted to be inked and having the form of a foil on which the image to be printed is present in positive form is clamped on the foil cylinder and from there transferred via a rubber-blanket cylinder to the paper which is to be printed. In the so-called direct printer, on the other hand, there is no rubber-blanket cylinder and the master which is clamped on the foil cylinder is a mirror image (or laterally inverted image) which is continuously inked and printed directly on the paper.

The desired number of copies can be set on such automatic machines by means of an adjustable counter which automtically shuts down themachine when the corresponding number of copies has been reached.

There are also electrostatic copy machines by which a master-copy pattern can be transferred to a coronacharged zinc oxide film after image differentiated exposure and fixed thereon. These zinc oxide films, after preliminary chemical treatment, can be used in an offset machine or a direct printer as master and can be repeatedly inked and printed for a relatively long run. As a result of the chemical pretreatment in which a potassium ferrocyanide solution is generally applied to the surface of the zinc oxide film, the film is made hydrophilic, so that the image which is to be printed can be inked with printing ink.

As is known, electrostatic or electrophotographic copy processes enter into consideration only for a small number of copies due to the time required and the price of such a copy.

It is one object of the present invention to provide a printing unit using a zinc oxide film produced by an electrostatic copy machine with the image to be duplicated from an original, without prior chemical treatment, directly from the electrostatic copy machine into the automatic printing unit, make it suitable for printing therein, and use it as printing foil for large runs (1000 copies).

The machine according to the present invention comprises an etching device for rendering a zinc oxide film hydrophilic and a sheet-insert device with a station consisting of a stop provided with feeler switches and capable of being swung out of the path of the film, a pair of transport rollers which can be driven synchronously with the foil cylinder passing the etching device via a single-revolution clutch, and a foil feed device, which conducts a printing foil coming from an electrostatic copy machine against the stop, and a grippingand ejection device which can be actuated from the outside.

The particular advantage of the printing machine of the invention is that it can be brought up to an existing electrostatic copy machine so as automatically to receive as printing foil a copy of an original produced in the copy machine, and then produce the desired number of printed copies. In this connection it is not necessary to effect any changes on theelectrostatic copy machine itself in order to obtain synchronization of the two machines and/or to subject the copy produced by the electrostatic copy machine to a prior chemical treatment before introducing it into the printing machine in order to make it suitable for printing. The entire operation of the printing machine can be started or brought about by feeler switches arranged on the swingable stop of the sheet-insert device, these two feeler switches not only verifying and guaranteeing the presence of the printing foil but also the proper position thereof.

In order to assure proper operation of the printing machine, commencing with the inserting of the printing foil into the foil cylinder and terminating with the ejection thereof, it is a feature of the invention that the single-revolution clutch be adapted to be engaged by a switch which is opened as a function of the feeler switches of the foil stop and a switch which is opened during the printing process and, in angle-true synchronism with respect to the gripper device of the foil cylinder, drives cams controlling the electrical switches and, via a form-locked transmissioma transport cylinder of the film insert device and cams in order to control the pressing cylinder of the pair of transport cylinders and the film stop.

In order further to increase the reliability in operation and the speed with which the functions are carried out, and therefore the operating speed and the output of the machine, the invention provides that the etching device and the inking unit can each be brought individually by electromagnets from a position of rest into operative positions, the electromagnets being controlled by switches which are actuated by cams which are in drive connection with the film cylinder or a transmission part operating synchronouly therewith via a coupling which is controlled electromagnetically as a function of a cam driven by thesingle-revolution clutch. In this way assurance is also had that the connecting and disconnecting both of the etching device and of the inking unit are controlled from the two feeler switches of the film stop and thus indirectly by the-film via the single-revolution clutch, and that another insertion of film is automatically prevented during the course of the printing run.

For the purpose also of assuring reliability in operation, another embodiment of the invention resides in associating with the cams a notched disk provided with two notches of different depth which are relatively angularly offset; at a small angle away from each other, the contour of the disk being sensed by a detent lever which acts on two switches which control the electromagnetic clutch. A self-holding function for the electromagnetic clutch is associated with one of these switches in cooperation with the detent lever, while the other switch has the job of bringing the notched disk into its starting position from the operating position, which it assumes during the course of the printing process upon attaining the preset number of the run by a pulse from the preselector counter provided for this.

The cams and the notched disk are driven in a ratio of about l5:l with respect to the film cylinder via a step-down gearing and assume a starting position produced by the detent lever as well as an operating position in which the functions of the printing process are connected and the circuit of the electromagnet actuating the single-revolution clutch is interrupted. Thus with a relatively small number of control elements, and thus with a small number of possible sources of error, various functions of the printing press can be initiated and terminated positively in predetermined sequence, such as the actuation and inactivation of the etching device, and, following same, the operation of the inking unit, in each case during a few revolutions of the film cylinder before the paper feed is connected and the actual printing process commences. At the same time, the functions concerning the film insertion which are controlled by the single-revolution clutch cannot be turned on again until the printing is at an end.

These and other objects will become more readily apparent from the following description, reference being made to the accompanying drawing, in which:

FIG. 1 is a schematic elevational view of the basic construction of an automatic printing press with an etching device and a film insert device;

FIG. 2 is a side-elevational view of the control mechanism of the single-revolution clutch;

FIG. 3 is a cross section taken along the line IIIIII of FIG. 2;

FIG. 4 is a side-elevational view of the control mechanism of the sheet insert device;

FIG. 5 is a side-elevational view taken along the line VV of FIG. 4;

FIG. 6 is a side-elevational view of the etching device with its control mechanism at an enlarged scale;

FIG. 7 is a side-elevational view of a pack of cams which controls a plurality of electric switches and is driven via an electromagnetically actuatable clutch and is equipped with a notched disc, which controls electric switches also via a detent lever;

FIG. 8 is a section taken along the line VIIIVIII of FIG. 7;

FIG. 9 is a schematic showing of the control mechanism of the gripping and ejection device of the film cylinder;

FIG. 10 is a section taken along the line X-X of FIG.

FIGS. 11, 12 and 13 are side-elevational views of different functional positions of the gripping and ejection device of the film cylinder; and

FIG. 14 is an electric wiring diagram of the the most important function-control parts of the machines.

FIGS. 1 and 5 show diagrammatically the overall construction of the printing press 1 in accordance with the present invention. The frame of the printing press 1 consists of two side plates 2 and 3 (FIG. 5), arranged vertically and spaced from each other, only one of which is visible in FIG. 1. Between these plates 2 and 3 there are provided, in addition to the film cylinder 4 and its back-pressure cylinder 5, a vertically adjustable paper supply table 6 and the corresponding paper feed device 7, an etching mechanism 8 and an inking unit 9, as well as a film feed device 10 which comprises a conveyor belt 11, a pair of conveyor rollers 12 consisting of drive rollers 13 and pressure rollers 14, as well as a swingable film stop 15 having two feeler switches E 3. Above the conveyor belt 11 there is arranged an infrared radiator 16 which serves for drying the zinc oxide films coming from an electrostatic copy machine 17 via a guide plate 18 onto the conveyor belt l1.

Between the film stop 15 and the film cylinder 4 there is located a guide plate 19 over which the zinc oxide film is conducted from the film-insert device into a gripping device (to be described later) of the film cylinder 4. Above the film cylinder 4 there is another guide plate 21 which, after the printing,-conveys the film ejected from the film cylinder 4 over another conveyor device 22 into a film delivery tray 23.

Between the stack 24 of printing paper present on the paper supply table 6 and the back-pressure cylinder 5 there are also located guide plates 25 and drive rollers 26 which conduct the individual paper sheets to be printed between the film cylinder 4 and the backpressure cylinder 5, where they are printed and after which they pass via a chute 27 into a printed-copy delivery tray 28.

The drive of the back-pressure cylinder 5 is provided by an electric motor 29 by means of a belt 30 which, via the two gears 31 and 32 having the same number of teeth, also drives the film cylinder 4 in synchronism with the back-pressure cylinder 5. By means of a toothed belt or a chain 33, the film cylinder 4 drives the driving part of a single-revolution clutch 34 and a pinion 35 which is in engagement with a gear 36 and, via an electromagnetically actuatable clutch 37 (see FIG. 8), drives a pack of cams 38 by which the electric switches E 10, E 11, E 12 and E 13 are actuated. The pack of cams 38 has four cams 39, 40, 41 and 42, each of which is associated with one of the switches E 10 to E 13. Furthermore the pack of cams 38 is equipped with a notched disk 43 which is formed on its circular periphery at a slight angular distance apart two detent notches 44 and 45 of different depth and is sensed by a spring-loaded cam-follower detent lever 46 having a detent nose 47. The detent lever 46 is swingably supported on a fixed pin 48 and is under the action of a tension spring 49. As a function of the operating position at the time of the notched disk 43, two electric switches E 21 and E 42 are actuated by the detent lever 46 (FIG. 7). I

The single-revolution clutch 34, which is shown in further detail'in FIGS. 2 and 3, consists of a lever arm 50 which is rotatably supported by means of two ball bearings 51 on a pin 52 of the side plates 3 and is rigidly connected with a sprocket wheel 53 which is driven by the drive chain 33 in synchronism with the film cylinder 4. At its outer end the lever arm 50 has a driving pawl 54 which, under the action of a tension spring 55, is pulled into engagement with a driving disk 56. The driving disk 56 has a stop nose 57 and is rotatably supported by means of two ball bearings 58, independently of the lever arm 50, on the pin 52. Furthermore, it is equipped with two cams 59 and 60 and with a sprocket wheel 61. The cams 59 and 60, independently of each other, actuate two electric switches E 8 and E 56, while the sprocket wheel 61 is in drive connection, via a drive chain 62, with an equally large sprocket wheel 63 of the film insert device 10 (see also FIGS. 4 and 5).

The engagement of the drive pawl 54 with the drive disk 58 is controlled by an electromagnet M 7 whose armature 64 is connected via a double-armed lever 65 and a strap 66 with a double-armed control lever 67 on whose free end there is a roller 68 which is disposed in the path of movement of the driving pawl 54. The lever 65 is rotatably supported on a stationary pin 69 and the lever 67 is rotatably supported on a stationary pin 69'. By means of a tension spring 70, the control lever 67 is pulled into the position shown in solid lines in FIG. 2 in which upon the passage of the roller 68, it lifts the driving pawl 54 out of engagement with the driving disk 56. There is also provided a detent pawl 72 which is swingably supported on a fixed pin 71 and is provided with a stop notch 73 and with a detent notch 74 into which a finger 75 of the lever 65 engages. To a bent arm 76 of the detent pawl 72 the second end of the tension spring 70 is attached; the spring 70 pulls the arm 76 into the path of movement 77 of the lever arm 50 of the single-revolution clutch 34 when the magnet M 7 is energized.

As can be noted from FIGS. 4 and 5, the tilt wheel 63 of the sheet-insertion device is seated firmly on a shaft 78 which is supported in the two side plates 2 and 3 and bears at its other end two control cams 79 and 80 as well as a sprocket wheel 81 and a notched disk 82. The cam 80 via an exploring lever 83 controls the film stop by means of the two feeler switches E 3 and the cam 79 controls the pressing roller 14 via a lever arm 84. While these two earns 79 and 80 are rigidly connected with the shaft 78, there is a pin-and-slot connection 85,86 between the cam 79 and the sprocket wheel 81 so that at the start of the movement of the shaft 78, a delay in drive of the sprocket wheel 81 by the length of the slot 86 and thus also a delay in drive of the transport roller 13 occurs, they being in drive connection with the sprocket wheel 81 by a drive chain 87 and a chaim pinion 88. The chain pinion 88 is seated on a shaft 89 supported in the side plates 2 and 3, said shaft bearing a plurality of drive rollers 13. The notched disk 82 is rigidly connected with the sprocket 81. A tension spring 90 which is attached to pin 91 of the notched disk 82 at the end of each rotation of the shaft 78 again does away with the delay in drive produced by the pin-and-slot connection 85,86, so that the slot 86, before each revolution of the shaft 78, assumes the position shown in FIG. 4 in which the pin 85 is at the rear end of the slot 86, seen in the direction of rotation. In this position, the sprocket wheel 81 and the notched disk 82 are secured by a detent lever 92 which is engaged with the notched disk 82. i

The etching device 8, which in known manner has a liquid trough 93 and an applicator roller 94 and serves to hydrophilize, i.e., make water-absorptive, a zinc oxide film drawn onto the film cylinder 4 before the inking, is controlled by a magnet M 14 (FIG. 6). For this purpose the armature 95 of the magnet M 14 is connected by a lever 96, swingably supported on a fixed pin 97, with the bearing plates 98 of the liquid trough 93 and the applicator roller 94 which are swingably supported on a shaft 99.

The gripping device of the film cylinder 4, as can be noted from FIGS. 11 13, consists of a plurality of gripper fingers 101 fastened on a shaft 100, the said fingers, in closed position of the gripping device 20, resting under spring action on a clamping ledge 102 on the circumference of the film cylinder 4 and holding fast the front edge of a film 103 which has been inserted. At the same time, there serve as stop and ejector lever 5, arms 104 consisting of flat stock which are also fixed on the shaft 100 and at their free end have rectangularly inwardly bent tongues 105 with beveled lift fingers force-locked engagement with a roller 109 of the one lever arm 110 of a double-armed lever 111 which is swingably supported on a pin 112 on the one end side of the film cylinder 4, while on its second lever arm 113 it bears a feeler roller 14. The feeler roller 14 is held by the spring 108 constantly in contact with the circumference of a circular cam disk 115 arranged in fixed position concentrically to the film cylinder 4, said cam having on its circumference at two suitable points spherically concave recesses 116 and 117. As can be noted from FIG. 10, the cam 115 is seated between the said side plate 2 and the one end side 118 of the film cylinder 4 on which the lever 110 with its feeler roller 14 is supported. The cam 115, in the embodiment shown in FIG. 10, is part of a bearing bushing 119 which is seated in a corresponding bore hole of the side plate 2 and firmly screwed to the plate 2. In the bearing bushing 119 there is rotatably supported by means of a ball bearing 120 a bearing tube 121 which, by means of two ball bearings 122, carries the shaft 1230f the film cylinder 4.

At its inner end the bearing tube 121 has a circular cover disk 124 with two spherically concave recesses 125 and 126 which are spaced 180 apart from each other, the diameter of the cover disk 124 being equal to the diameter of the cam disk 115. At its outer end the bearing tube 121 has a flange 127 with which a friction wheel 128 and a notched disk 129 having a plurality of detent notches 130 are fastened. The friction wheel 128 furthermore bears two pins 131 and 132 which actuate a switch E 22 when the cover disk 124 has reached its starting position. On the outer end of the shaft 123 of the film cylinder 4 there is seated a gear 133 which, via a transmission gearing 134, 135, drives a friction roller 137 which is supported by a swing lever 136 and can be brought by corresponding swinging of the swing lever136 in force-locked engagement with the friction wheel 128. The swing lever 136 is connected with the armature 138 of a magnet M 9 and has a detent finger 139 which, in given operating positions of the cover disk 124, drops into the detent notches 130 of the notched disk 129 when the electromagnet M 9 is disconnected and the tension spring 140 pulls the armature 138 downward.

FIG. 14, the most important electric switching and control circuits of the printing press of the invention are shown in a comprehensive wiring diagram. Both the circuit within the dash-dot framing 140 of the drive motor 29 and the control circuit of the reversing motor 141 which drives the paper-supply table 6 shown within the dot-dash frame 142 as well as the circuit of the three-decade electric preselection counter 144 contained in the dot-dash frame 143 are of known type so that these circuits need not be described in detail. By means of a switch relay S 49, the two lines 146 and 147 can be connected to the power line terminal 145. To the two lines 146 and 147 there are connected the control circuits of the electromagnets M 14, M 15, M 16 as well as M 7 and M 9. The electromagnets M 14, M 15 and M 16 are in series with the switches E 10, E 11 and E 12. In the circuit of the electromagnet M 7 there are connected in series the two feeler switches E 3, a switch E 4 and a pushbutton switch 147 to which an indicating lamp 148 is connected in parallel.

In the circuit of the electromagnet M 9 there are contained the switch E 8 and parallel thereto the switches 7 E 13 and E 22, E 13 and E 22 being in series with each other.

In the same way as the electric counter 144, the electromagnetic clutch 37 is operated with direct current which is obtained from a rectifier 149 which is connected to a transformer 150. In the circuit of the electromagnetic clutch 37 there is contained a working contact 01 of a relay A. One end of the winding of the relay A can be connected by a changeover contact ul with the negative terminal of the rectifier 149, while the other end of the winding is connected at the one side with the output Z of the electric counter 144 and at the other side with the switches E 42 and E 56 as well as with the manual switch 150. The two switches E 42 and E 56 are connected in parallel with each other and are attached on the other end jointly to the positive terminal of the rectifier 149 to which the work contact al of the relay A is also connected. The changeover contact ul is actuated by a relay U, as well as the changeover contact u2 which lies between the switch E 21 and the manual switch 150. The switch E 21 has a changeover contact 153 which is connected at the one end via the changeover contact u 2 to the one terminal of the manual switch 150 and on the other hand via a capacitor 152 to the positive terminal of the rectifier 149. The stationary contact 154 of the switch E 21 is connected, via a resistor 151, to the positive terminal of the rectifier 149, while the other stationary contact 155 is connected with one end of the winding of the relay U whose other end is also connected to the positive terminal of the rectifier 149.

A switch E 23 transfers the counting pulses to the electrical counter 144.

The manner of operation of the printing press whose construction is described above is as follows:

When the switch relay S 49 is connected by corresponding actuation of the main switch of the machine and the drive motor 29 and the two lines 146 and 147 (FIG. 14) are connected to the powerline terminals 145, the machine is ready to operate. The number of copies in the run can be set on the presettable electric counter 144. As soon as a zinc oxide film 103 arrives from the electrostatic copy machine 17 via the guide plate 18 onto the conveyor belt 11, its front edge is brought against the film stop and thus when the film rests over its entire width parallel against the film stop 15, the two switches E 3 are closed (FIGS. 1 and 14). As a result, the indicating bulb 148 then lights up, indicating that the zinc oxide film 103 is ready to be inserted. By a brief closing of the pushbutton switch 147, the electromagnet M 7 is then energized. The switch E 4 which is connected in series with the pushbutton switch 147 and the two feeler switches E 3 is closed in this condition of the machine, since the notched disk 43 (FIGS. 7 and 8) and the detent lever 46 assume their rest position. By the energizing of the electromagnet M 7, the lever 67 together with the control roller 68 is swung out of the path of movement of the driving pawl 54 into the position shown in dashed line in FIG. 2 and held by the detent pawl 72 until the lever arm 50 passes by its arm 76 and swings the pawl in clockwise direction so that the finger 75 again leaves the detent notch 74 and falls back into the stop notch 73. Before this takes place, however, the driving pawl 54 comes into engagement with the driving nose 57 of the driving disk 56, so that the driving disk 46 is driven along for a complete revolution by the lever arm 50. When the revolution is complete, the driving pawl 54 is brought out of engagement again by the control roller 68 of the lever 67, so that the lever arm 50 from now on turns further idling. During this single revolution, the two cam disks 59 and 60 operate in synchronism with the film cylinder 4 and actuate the switches E 8 and E 56 (FIGS. 2, 3 and 14). The switch E 8 is briefly closed two times in succession by the cam disk 59 and the electromagnet M 9 is thereby energized in such a manner that by the swinging of the swing lever 136 (FIG. 9), it brings the friction roller 137 into engagement with the friction wheel 128 and swings the cover disk 124 from the position shown in FIG. 12 into the position shown in FIG.

11 in which the recess 125 coincides with the recess 117 of the control disk 115, so that the feeler roller 114 of the lever can drop into the recess 117 and the spring 108 can briefly open the grip device 20 so as to receive the arriving zinc oxide film 103 and thereupon hold it fast. As soon as the feeler roller 114 has again left the recess 117 in a counter-clockwise direction of rotation, the electromagnet M 9 is again energized by the switch E 8 until the control disk has completely carried out half a revolution and both recesses 116 and 117 of the control disk 115 are again covered. The film insert device 10 with the cams 79 and 80 is thereby driven simultaneously for one revolution, as are the transport rollers 13. In this connection the film stop 15 is first of all swung by the cam 80 out of the path of the transport of the film into the position shown in solid lines in FIG. 4. Immediately thereupon the pressing roller 14 is lowered against the zinc oxide film by the cam 79 so that it presses the transport rollers 13 against same, which rollers are now also driven, since the pin 85 has in the meantime reached the other end of the slot 86 of the sprocket wheel 81 and drives the latter. By the synchronous operation between the film cylinder 4, the cams 59 and 60 and the earns 79 and 80, obtained by the single-revolution clutch 34 and the delayed synchronous operation of the sprocket wheel 81 which, via the sprocket pinion 88, drives the shaft 89 with the transport rollers 13, assurance is had that the zinc oxide film 103 which is inserted in this manner reaches the gripping device 20 of the film cylinder 4 just at the time that it is opened so as to be clamped fast therein and to be held fast on the cylindrical surface of the film cylinder 4 during the further revolutions thereof.

During the inserting of the film, the switch E 56 is closed briefly by the cam 60 of the single-revolution clutch 34, the switching causing the reponse of the relay A (FIG. 14) which, by closing its contact a1, energizes the electromagnetic clutch 37 and thereby produces the drive connection between the sprocket wheel 36 and the bundle of cams 38 (FIG. 8). In this way the notched disk 43 is also driven in counter-clockwise direction, so that the detent nose 47 of the detent lever 46 leaves the deep notch 45 and is swung in clockwise direction, it opening the switch E 4, closing the switch E 42 and shifting the changeover contact 153 of the switch E 21 from contact 155 to contact 154. By the closing of the switch E 42, the relay A, even after the opening of the switch E 56, is maintained under voltage, so that the clutch 37 remains energized and the bundle of cams 38 turns further. The switch E 42 remains closed until the bundle of earns 38 with the notched disk 43 has carried out practically a complete revolution, which, as a result of the transmission ratio selected, requires about 15 revolutions of the film cylinder, and the detent nose 47 of the detent lever 46 drops into the notch 44 which is only half as deep as the detent notch 45. As a result of the slight swinging movement of the detent lever 46 in clockwise direction, only the switch E 42 is opened again, while no switching takes place on the switch E 21. The capacitor 152 thus remains connected by the switch E 21 via the resistor 151 to the two poles of the rectifier 149. The relay U during this entire time is still not energized, so that its two contacts ul and a2 up to now still are in the position shown in FIG. 14, one winding of the relay A being connected continuously via the contact ul with the negative terminal of the rectifier 149. Upon the opening of the switch E 42 when the detent lever 46 drops into the smaller detent notch 44 (FIG. 7), the circuit of the relay A is opened and thus the circuit of the electromagnetic clutch 37 (FIG. 8) is also interrupted. This means that the notched disk 43 with the cam bundle 38 also remains stopped for the time being.

After the pulling of the zinc oxide film 103 onto the film cylinder 4, the electromagnet M 14 (FIGS. 1 and 6) first of all is energized for a few revolutions of the film cylinder 4 by the cam 39 and the switch E 10, the electromagnet thereby bringing the applicator roller 94 of the etching device 8 into contact with the film cylinder 4 and the zinc oxide film 103 present thereon in order to make its surface water-absorptive. As etching liquid, a potassium iron cyanide solution can be used. When the hydrophilizing process is at an end and the applicator roller 94 has been again lifted off from the zinc oxide film 103 on the film cylinder 4 by the disconnecting of the electromagnet M 14, the inking unit 9 is first of all connected by the closing of the switch E 11 by means of an electromagnet M 15 (FIGS. 1 and 14) and the applicator rollers of the inking unit are pressed in known manner against the surface of the film cylinder 4, so that the zinc oxide film is inked in imagedifferentiated fashion on its surface. After a few revolutions of the film cylinder 4, the paper feed 7 is then also connected and the back-up cylinder pressed against the film cylinder 4, so that the actual printing process then commences and the individual sheets of paper are removed independently from the paper-supply stack 24 on the paper-supply table 6, fed between the film cylinder 4 and the back-up cylinder 5, printed and finally delivered to the delivery tray 28 (FIG. 1). For each printed sheet, the switch E 23 gives offa counting pulse to the electrical counter 144 which has been preset to a given value until said preset value has been reached. The relay A then receives a pulse, as a result of which the electromagnetic clutch 37 (FIGS. 8 and 14) is energized for a short time so as to turn the bundle of cams 38 and the notched disk 43 until the detent lever 46 now comes into the lower detent notch 45, it simultaneously switching the switch E 21 back into its starting position. By this switching of the switch E 21, the capacitor 152 is discharged over the relay U which is thereby energized and reverses its contacts ul and M2 briefly, so that the relay A drops out and the electromagnetic clutch 37 is disconnected.

An interruption of the printing can also be effected in advance by closing the pushbutton switch 150, whereby the relay A is then energized via the resistor 151, the switch E 21, the contact a2 and the pushbutton switch 150 so as briefly to close the circuit of the electromagnetic clutch 37 and move the notched disk 43 with the cam bundle 38 into the starting position.

As soon as the cam bundle 38, and in particular the cam 42, has reached the starting position, the switch E 13 is closed, while the switches E 10, E 11, E 12 are again opened. The closing switch E 13 again energizes the electromagnet M 9 via the switch 33 closed at this time (FIGS. 9 and 10), so that the electromagnet brings the continuously rotating friction roller 137 into en gagement with its friction wheel 128 and drives the cover disk 124 in clockwise direction (referred to FIGS. 9, 11, 12 and 13) until the recess 126 coincides with the recess 116 of the cam 115, and, as shown in FIG. 13, the lever 110 can release the pawl 107 to such an extend that during the further rotation of the film cylinder 4, the zinc oxide film 103 is lifted onto the guide plate 121 by the tongues of the lever arm 104 or the lifting fingers thereof and passes, via the transport device 22 (FIG. 1) to the delivery 23. The entire cycle of the machine is now at an end and if a new zinc oxide film 103 already rests agains the film stop 15 (FIG. 1), a new cycle can be started, in the manner which has just been described.

It should also be mentioned that the disconnecting of the electromagnet M 9 and thus of the drive of the cover disk 124 is effected by theopening of the switch E 22, namely by the switch finger 131 (FIGS. 9 and 10), which just reaches the switch when the two recesses 126 and 116 coincide.

Of course, it is also possible to use the printing press 1 of the invention independently of an electrostatic copy machine 17 for printing if suitable films are available, in the same way as it is possible also to use the electrostatic copy machine 17 in traditional fashion by itself merely in order to produce electrostatic copies. While, however, as already mentioned, it is very timeconsuming and expensive to make a large number of copies of one and the same master with an electrostatic copy machine, the printing machine of the invention affords the advantage that on the one hand it gives better printed copies than the electrostatic copy machine 17 and that substantially larger runs of constant quality can be produced cheaper in a substantially shorter period time.

We claim:

1. In an automatic printing machine comprising:

a master-feed station adapted to receive a succession of zinc oxide masters;

abutment means at said master-feed station for temporarily retaining each of said masters at said station;

a pair of transport rollers adjacent said master-feed station for engagement with a. master upon release thereof by said abutment means;

a continuously driven film cylinder spaced from said transport rollers and provided with means engageable with a master for wrapping same around and releaseably retaining the master on said cylinder;

first guide means forming a transport path between said transport rollers and said cylinder for delivering a master advanced by said transport rollers to said cylinder for engagement therewith;

pressure means juxtaposed with said cylinder and synchronously coupled therewith for pressing a copy sheet against a master wrapped around said cylinder to transfer copy from the master on said cylinder to said sheet;

copy-sheet feed means for delivering a succession of copy sheets between said master wrapped around said cylinder and said pressure means;

second guide means for conducting said copy sheets away from said cylinder and said pressure means upon the transfer of copy to said sheets; and

a presettable counter responsive to the number of copy sheets conducted along said second guide means for terminating further advance of copy sheets and ejecting the master wrapped around said cylinder;

the improvement which comprises:

first rotatable cam means at said master-feed station for displacing said abutment means to release a master for engagement and displacement by said transport rollers and for shifting one of said transport rollers to engage a released master between them;

means coupling one of said transport rollers with said first cam means for synchronous rotation therewith to advance said released master on said first guide means;

a single-revolution clutch operatively connected to said first cam means for rotating said first cam means synchronously with said clutch upon actuation thereof;

means operatively connecting said singlerevolution clutch with said cylinder for synchronous rotation of said cylinder and said singlerevolution clutch upon actuation thereof;

feeler switch means on said abutment means and displaceable therewith out of the path of a released master, said feeler switch means being positioned to sense the presence of a master at said means and said single-revolution clutch for actuating same upon the sensing of the presence of a master at said station by said feeler switch means;

second cam means rotatably connected to said single-revolution clutch;

a first cam-operated switch cooperating with said second cam means and operatively connected to said means engageable with said master for enabling the entrainment of the released master displaced along said first guide means by said cylinder;

hydrophilizing means along the periphery of said cylinder for treating a master wrapped thereon to render the same wettable for subsequent imagedifferentiated inking;

inking means along said drum for applying ink to a hydrophilized master wrapped therearound; and

a second cam-operated switch cooperating with said second cam means and operatively connected with said hydrophilizing means for bringing same into engagement with a master wrapped on said cylinder.

2. The improvement defined in claim 1, further comprising:

a third cam-operated switch actuated by said first cam means;

a further clutch synchronously rotated with said cylinder upon actuation by said third cam-operated switch;

third cam means driven by said further clutch; and

a fourth cam-operated switch actuated by said third cam means for rendering said inking means effective. 

1. In an automatic printing machine comprising: a master-feed station adapted to receive a succession of zinc oxide masters; abutment means at said master-feed station for temporarily retaining each of said masters at said station; a pair of transport rollers adjacent said master-feed station for engagement with a master upon release thereof by said abutment means; a continuously driven film cylinder spaced from said transport rollers and provided with means engageable with a master for wrapping same around and releaseably retaining the master on said cylinder; first guide means forming a transport path between said transport rollers and said cylinder for delivering a master advanced by said transport rollers to said cylinder for engagement therewith; pressure means juxtaposed with said cylinder and synchronously coupled therewith for pressing a copy sheet against a master wrapped around said cylinder to transfer copy from the master on said cylinder to said sheet; copy-sheet feed means for delivering a succession of copy sheets between said master wrapped around said cylinder and said pressure means; second guide means for conducting said copy sheets away from said cylinder and said pressure means upon the transfer of copy to said sheets; and a presettable counter responsive to the number of copy sheets conducted along said second guide means for terminating further advance of copy sheets and ejecting the master wrapped around said cylinder; the improvement which comprises: first rotatable cam means at said master-feed station for displacing said abutment means to release a master for engagement and displacement by said transport rollers and for shifting one of said transport rollers to engage a released master between them; means coupling one of said transport rollers with said first cam means for synchronous rotation therewith to advance said released master on said first guide means; a single-revolution clutch operatively connected to said first cam means for rotating said first cam means synchronously with said clutch upon actuation thereof; means operatively connecting said single-revolution clutch with said cylinder for synchronous rotation of said cylinder and said single-revolution clutch upon actuation thereof; feeler switch means on said abutment means and displaceable therewith out of the path of a released master, said feeler switch means being positioned to sense the presence of a master at said station; means operatively connecting said feeler switch means and said single-revolution clutch for actuating same upon the sensing of the presence of a master at said station by said feeler switch means; second cam means rotatably connected to said single-revolution clutch; a first cam-operated switch cooperating with said second cam means and operatively connected to said means engageable with said master for enabling the entrainment of the released master displaced along said first guide means by said cylinder; hydrophilizing means along the periphery of said cylinder for treating a master wrapped thereon to render the same wettable for subsequent image-differentiated inking; inking means along said drum for applying ink to a hydrophilized master wrapped therearound; and a second cam-operated switch cooperating with said second cam means and operatively connected with said hydrophilizing means for bringing same into engagement with a master wrapped on said cylinder.
 2. The improvement defined in claim 1, further comprising: a third cam-operated switch actuated by said first cam means; a further clutch synchronously rotated with said cylinder upon actuation by said third cam-operated switch; third cam means driven by said further clutch; and a fourth cam-operated switch actuated by said third cam means for rendering said inking means effective. 